Downregulation of ITM2A Gene Expression in Macrophages of Patients with Ankylosing Spondylitis

Objectives: Ankylosing spondylitis (AS) is a rheumatic disorder that is mostly determined by genetic and environmental factors. Given the known importance of macrophage in AS pathogenesis, we investigated the transcriptional profile of macrophage cells in the disease. Methods and Results: Two approaches of differential expression and subsequently, weighted gene co-expression network analysis was utilized to analyze a publicly available microarray dataset of macrophages. Integral membrane protein 2A (ITM2A) was among the most significant genes with a decreased trend in the common results of both methods. In order to confirm the finding, the expression of ITM2A was evaluated in monocyte-derived (M2-like) and M1 macrophages obtained from 14 AS patients and 14 controls. Macrophages were differentiated from whole-blood separated monocytes by 7 days incubating with macrophage colony-stimulating factor and then macrophages specific markers were verified with the flow cytometer. M1 polarization was induced by IFN-gamma and lipopolysaccharide. Finally, relative gene expression analysis by real-time polymerase chain reaction revealed a significant downregulation of the ITM2A gene in both M2 like and M1 macrophages of the AS group compared to the control. Conclusion: Since ITM2A plays a critical role in osteo- and chondrogenic cellular differentiation, our finding may provide new insights into AS pathogenesis.Peer reviewe

Voltage-Gated Sodium Channels Modulation by Bothutous Schach Scorpion Venom: Detection of sodium blocker fraction on scorpion venom

Buthotus schach is one of the dangers scorpions in Iran that belong to the Buthidae family. Toxins are existing in venom scorpion, modulate the ion channels by blocking or opening the pore of the channel or by altering the voltage gating and useful as pharmacological tools. In the present study, we investigated the effects of venom and its obtained fractions by gel filtration on electrophysiological properties of magnocellular supraoptic of hypothalamus by using whole cell patch clamp. Our results shown indicated scorpion crude venom and its fraction effect on voltage gated sodium channels. A significant decrease was revealed in amplitude firing, in venom various concentration and some of the venom fractions. Also, a significant increase was shown in half width and rise time 10% to 90% actions potential firing. Previous evidence revealed a change in electrophysiological properties such as amplitude and rise time 10% to 90%, related to voltage gated sodium channels. Sodium channels toxins existed on scorpion venom caused modulate on sodium channels. In order to access bioactive components, six fractions were collected by gel chromatography techniques. After bath application of fractions, F2 and F3 components show the same effects than venom on electrophysiological properties of magnocellular supraoptic

Voltage-Gated Sodium Channels Modulation by Bothutous Schach Scorpion Venom

Abstract Buthotus schach is one of the dangers scorpions in Iran that belong to the Buthidae family. Toxins are existing in venom scorpion, modulate the ion channels by blocking or opening the pore of the channel or by altering the voltage gating and useful as pharmacological tools. In the present study, we investigated the effects of venom and its obtained fractions by gel filtration on electrophysiological properties of magnocellular supraoptic of hypothalamus by using whole cell patch clamp. Our results shown indicated scorpion crude venom and its fraction effect on voltage gated sodium channels. A significant decrease was revealed in amplitude firing, in venom various concentration and some of the venom fractions. Also, a significant increase was shown in half width and rise time 10% to 90% actions potential firing. Previous evidence revealed a change in electrophysiological properties such as amplitude and rise time 10% to 90%, related to voltage gated sodium channels. Sodium channels toxins existed on scorpion venom caused modulate on sodium channels. In order to access bioactive components, six fractions were collected by gel chromatography techniques. After bath application of fractions, F2 and F3 components show the same effects than venom on electrophysiological properties of magnocellular supraoptic

Preventing effect of L-type calcium channel blockade on electrophysiological alterations in dentate gyrus granule cells induced by entorhinal amyloid pathology.

The entorhinal cortex (EC) is one of the earliest affected brain regions in Alzheimer's disease (AD). EC-amyloid pathology induces synaptic failure in the dentate gyrus (DG) with resultant behavioral impairment, but there is little known about its impact on neuronal properties in the DG. It is believed that calcium dyshomeostasis plays a pivotal role in the etiology of AD. Here, the effect of the EC amyloid pathogenesis on cellular properties of DG granule cells and also possible neuroprotective role of L-type calcium channel blockers (CCBs), nimodipine and isradipine, were investigated. The amyloid beta (Aβ) 1-42 was injected bilaterally into the EC of male rats and one week later, electrophysiological properties of DG granule cells were assessed. Voltage clamp recording revealed appearance of giant sIPSC in combination with a decrease in sEPSC frequency which was partially reversed by CCBs in granule cells from Aβ treated rats. EC amyloid pathogenesis induced a significant reduction of input resistance (Rin) accompanied by a profound decreased excitability in the DG granule cells. However, daily administration of CCBs, isradipine or nimodipine (i.c.v. for 6 days), almost preserved the normal excitability against Aβ. In conclusion, lower tendency to fire AP along with reduced Rin suggest that DG granule cells might undergo an alteration in the membrane ion channel activities which finally lead to the behavioral deficits observed in animal models and patients with early-stage Alzheimer's disease

Rabies virus glycoprotein enhances spatial memory via the PDZ binding motif

“This is a pre-print of an article published in J. Neurovirol. The final authenticated version is available online at: https://doi.org/10.1007/s13365-021-00972-2”International audienceRabies is a life-threatening viral infection of the brain. Rabies virus (RABV) merely infects excitable cells including neurons provoking drastic behaviors including negative emotional memories. RABV glycoprotein (RVG) plays a critical role in RABV pathogenesis. RVG interacts with various cytoplasmic PDZ (PSD-95/Dlg/ZO-1) containing proteins through its PDZ binding motif (PBM). PTZ domains have crucial role in formation and function of signal transduction. Hippocampus is one of the cerebral regions that contains high load of viral antigens. We examined impact of RVG expression in the dorsal hippocampus on aversive as well as spatial learning and memory performance in rats. Two μl of the lentiviral vector (~108 T.U. /ml) encoding RVG or ∆RVG (deleted PBM) genomes was microinjected into the hippocampal CA1. After one week, rat’s brain was cross-sectioned and RVG/∆RVG-expressing neuronal cells were confirmed by fluorescent microscopy. Passive avoidance and spatial learning and memory were assessed in rats by Shuttle box and Morris water maze (MWM). In the shuttle box, both RVG and ∆RVG decreased the time spent in the dark compartment compared to control (p<0.05). In MWM, RVG and ∆RVG did not affect the acquisition of spatial task. RVG-expressing rats reached the platform position in the probe test sooner than control and ∆RVG groups (p<0.05). Rats expressing ∆RVG significantly swam farther from the hidden platform than RVG group (p<0.05). Our data indicate RVG expression in the hippocampus strengthens aversive and spatial learning and memory performance. The boosting effect on spatial but not avoidance memory is mediated through PBM

Latent toxoplasmosis impairs learning and memory yet strengthens short-term and long-term hippocampal synaptic plasticity at perforant pathway-dentate gyrus, and Schaffer collatterals-CA1 synapses

Abstract Investigating long-term potentiation (LTP) in disease models provides essential mechanistic insight into synaptic dysfunction and relevant behavioral changes in many neuropsychiatric and neurological diseases. Toxoplasma (T) gondii is an intracellular parasite causing bizarre changes in host’s mind including losing inherent fear of life-threatening situations. We examined hippocampal-dependent behavior as well as in vivo short- and long-term synaptic plasticity (STP and LTP) in rats with latent toxoplasmosis. Rats were infected by T. gondii cysts. Existence of REP-529 genomic sequence of the parasite in the brain was detected by RT-qPCR. Four and eight weeks after infection, spatial, and inhibitory memories of rats were assessed by Morris water maze and shuttle box tests, respectively. Eight weeks after infection, STP was assessed in dentate gyrus (DG) and CA1 by double pulse stimulation of perforant pathway and Shaffer collaterals, respectively. High frequency stimulation (HFS) was applied to induce LTP in entorhinal cortex-DG (400 Hz), and CA3-CA1 (200 Hz) synapses. T. gondii infection retarded spatial learning and memory performance at eight weeks post-infection period, whereas inhibitory memory was not changed. Unlike uninfected rats that normally showed paired-pulse depression, the infected rats developed paired-pulse facilitation, indicating an inhibitory synaptic network disruption. T. gondii-infected rats displayed strengthened LTP of both CA1-pyramidal and DG-granule cell population spikes. These data indicate that T. gondii disrupts inhibition/excitation balance and causes bizarre changes to the post-synaptic neuronal excitability, which may ultimately contribute to the abnormal behavior of the infected host

Lentiviral Expression of Rabies Virus Glycoprotein in the Rat Hippocampus Strengthens Synaptic Plasticity

“This is a pre-print of an article published in journal of Cellular and Molecular Neurobiology. The final authenticated version is available online at: https://doi.org/10.1007/s10571-020-01032-9"International audienceRabies virus (RABV) is a neurotropic virus exclusively infecting neurons in the central nervous system. RABV encodes five proteins. Among them, the viral glycoprotein (RVG) plays a key role in viral entry into neurons and rabies pathogenesis. It was shown that the nature of the C-terminus of the RABV G protein, which possesses a PDZ-binding motif (PBM), modulates the virulence of the RABV strain. The neuronal protein partners recruited by this PBM may alter host cell function. This study was conducted to investigate the effect of RVG on synaptic function in the hippocampal dentate gyrus (DG) of rat. Two μl (108 T.U./ml) of the lentiviral vector containing RVG gene was injected into the DG of rat hippocampus. After 2 weeks, the rat’s brain was cross-sectioned and RVG-expressing cells were detected by fluorescent microscopy. Hippocampal synaptic activity of the infected rats was then examined by recording the local field potentials from DG after stimulation of the perforant pathway. Short-term synaptic plasticity was also assessed by double pulse stimulation. Expression of RVG in DG increased long-term potentiation population spikes (LTP-PS), whereas no facilitation of LTP-PS was found in neurons expressing δRVG (deleted PBM). Furthermore, RVG and δRVG strengthened paired-pulse facilitation. Heterosynaptic long-term depression (LTD) in the DG was significantly blocked in RVG-expressing group compared to the control group. This blockade was dependent to PBM motif as rats expressing δRVG in the DG-expressed LTD comparable to the RVG group. Our data demonstrate that RVG expression facilitates both short- and long-term synaptic plasticity in the DG indicating that it may involve both pre- and postsynaptic mechanisms to alter synaptic function. Further studies are needed to elucidate the underlying mechanisms

Systems Biomedicine of Rabies Delineates the Affected Signaling pathways

The prototypical neurotropic virus, rabies, is a member of the Rhabdoviridae family that causes lethal encephalomyelitis. Although there have been a plethora of studies investigating the etiological mechanism of the rabies virus and many precautionary methods have been implemented to avert the disease outbreak over the last century, the disease has surprisingly no definite remedy at its late stages. The psychological symptoms and the underlying etiology, as well as the rare survival rate from rabies encephalitis, has still remained a mystery. We, therefore, undertook a systems biomedicine approach to identify the network of gene products implicated in rabies. This was done by meta-analyzing whole-transcriptome microarray datasets of the CNS infected by strain CVS-11, and integrating them with interactome data using computational and statistical methods. We first determined the differentially expressed genes (DEGs) in each study and horizontally integrated the results at the mRNA and microRNA levels separately. A total of 61 seed genes involved in signal propagation system were obtained by means of unifying mRNA and microRNA detected integrated DEGs. We then reconstructed a refined protein-protein interaction network (PPIN) of infected cells to elucidate the rabies-implicated signal transduction network (RISN). To validate our findings, we confirmed differential expression of randomly selected genes in the network using Real-time PCR. In conclusion, the identification of seed genes and their network neighborhood within the refined PPIN can be useful for demonstrating signaling pathways including interferon circumvent, toward proliferation and survival, and neuropathological clue, explaining the intricate underlying molecular neuropathology of rabies infection and thus rendered a molecular framework for predicting potential drug targets

Calcium channel blockers, isradipine and nimodipine, prevent abnormalities in spontaneous IPSCs of DG granule cells caused by amyloid pathology in the EC.

<p>A, amplitude of spontaneous IPSCs increased in the EC-Aβ (lower trace) in contrast with the control (upper trace) neurons and there is a significant decrease in monoexponential decay time constant (fast inactivated) compared to the control cells (right plot, p < 0.05). B, cumulative probability plots showed that spontaneous events in the granule cells from Aβ treated rats shifted to larger amplitude (**p = 0.004 by Kolmogorov–Smirnoff test) and the change was blocked by isradipine and nimodipine. C, the amplitude of sIPSC significantly increased in granule cells from Aβ treated rats compared to the control, and isradinpine and nimodipine blocked the change. Cumulative probability plot (D) and mean frequency of spontaneous IPSCs (E) were unaltered between groups. Values are mean ± SEM. ***p < 0.001 contrasted to the control cells, ^##p < 0.01 and ^#p < 0.05 compared to EC-Aβ group. Control group, n = 6 cells/ 4 rats; EC-Aβ group, n = 8 cells/ 6 rats; EC-Aβ + ISR and EC-Aβ + NIM, n = 6 cells/ 4 rats.</p